The present invention relates to a process for producing or recovering 1,1,1,5,5,5-hexafluoroacetylacetone, which is useful as an intermediate for medicines and agricultural chemicals or an agent for a process producing electric parts and the like, and particularly to a process for producing or recovering this compound with high purity.
A large amount of a waste containing a metal complex of 1,1,1,5,5,5-hexafluoroacetylacetone is discharged and dumped, after the deposition of this metal complex by CVD in the production of electric parts. This dumping is not desirable from the viewpoints of the production cost and the environmental impact.
A. Henne et al., J. Amer. Chem. Soc., Vol. 69, pp. 1819-1820 (1947) discloses a process for producing anhydrous 1,1,1,5,5,5-hexafluoroacetylacetone by removing copper from a copper complex of 1,1,1,5,5,-hexafluoroacetylacetone with hydrogen sulfide in ether.
U.S. Pat. No. 6,046,364 discloses a process for recovering a 1,1,1,5,5,-hexafluoro-2,4-pentanedione ligand from a metal-ligand complex byproduct such as Cu2+(1,1,1,5,5,5-hexafluoro-2,4-pentanedionatexe2x88x921)2, comprising: providing a copper-ligand complex byproduct of Cu2+(1,1,1,5,5,5-hexafluoro-2,4-pentanedionatexe2x88x921)2 in a process stream; cooling and condensing the copper-ligand complex byproduct of Cu2+(1,1,1,5,5,5-hexafluoro-2,4-pentanedionatexe2x88x921)2 to separate it from the process stream; contacting the copper-ligand complex byproduct of Cu2+(1,1,1,5,5,5-hexafluoro-2,4-pentanedionatexe2x88x921)2 with a protonation agent, such as: sulfuric acid, hydrochloric acid, hydroiodic acid, hydrobromic acid, trifluoroacetic acid, trifluoromethanesulfonic acid, acid ion exchange resin, hydrogen sulfide, water vapor and mixtures thereof; and recovering 1,1,1,5,5,-hexafluoro-2,4-pentanedione. It is disclosed in this publication that the equation of using H2SO4 as the protonating agent in the Hhfac regeneration step is:
Cu(hfac)2+H2SO4xe2x95x90CuSO4+2Hhfac
where (hfac) is 1,1,1,5,5,-hexafluoro-2,4-pentanedionate, and Hhfac is 1,1,1,5,5,-hexafluoro-2,4-pentanedione. It is further disclosed therein that hydrogen sulfide or water, typically as vapor, could be used as the protonation agents.
It is therefore an object of the present invention to provide a process for producing or recovering 1,1,1,5,5,5-hexafluoroacetylacetone from a metal complex of 1,1,1,5,5,5-hexafluoroacetylacetone.
It is another object of the present invention to provide a process for producing a 1,1,1,5,5,5-hexafluoroacetylacetone hydrate, which is an intermediate for 1,1,1,5,5,-hexafluoroacetylacetone, from a metal complex of 1,1,1,5,5,5-hexafluoroacetylacetone.
According to the present invention, there is provided a process for producing a 1,1,1,5,5,-hexafluoroacetylacetone hydrate. This process comprises hydrolyzing a metal complex of 1,1,1,5,5,-hexafluoroacetylacetone into said hydrate.
According to the present invention, there is provided a process for producing 1,1,1,5,5,5-hexafluoroacetylacetone. This process comprises (a) hydrolyzing a metal complex of 1,1,1,5,5,5-hexafluoroacetylacetone into a 1,1,1,5,5,5-hexafluoroacetylacetone hydrate; and (b) dehydrating said hydrate into said 1,1,1,5,5,5-hexafluoroacetylacetone
It is possible to recover 1,1,1,5,5,5-hexafluoroacetylacetone from a metal complex of 1,1,1,5,5,5-hexafluoroacetylacetone by a process of the invention. This process comprises (a) hydrolyzing this metal complex into a 1,1,1,5,5,5-hexafluoroacetylacetone hydrate (e.g., 1,1,1,5,5,5-hexafluoroacetylacetone dihydrate); and (b) dehydrating this hydrate into 1,1,1,5,5,5-hexafluoroacetylacetone. It is possible by this process to easily obtain 1,1,1,5,5,5-hexafluoroacetylacetone with high purity, which is usable for producing medicines and agricultural chemicals or processing electric parts.
The metal complex of 1,1,1,5,5,5-hexafluoroacetylacetone to be used in the invention is not particularly limited, and it may be one prepared by any process. For example, it may be one prepared by a process for producing 1,1,1,5,5,5-hexafluoroacetylacetone metal complexes. Furthermore, the metal complex may be one which has been recovered after its use in a film formation by CVD or in a purification for producing high purity metals.
The metal complex can be produced, for example, by reacting 1,1,1-trifluoroacetone with an ester of trifluoroacetic acid to obtain 1,1,1,5,5,5-hexafluoroacetylacetone and then by reacting this 1,1,1,5,5,5-hexafluoroacetylacetone with a metal compound (e.g., cuprous oxide, cuprous chloride and copper(II) sulfate) in a solvent. Metal of the metal complex is not particularly limited, and can be selected from copper, uranium, chromium, iron and the like. Of these, copper is the most preferable.
In order to achieve the object of the invention, it suffices that the metal complex contains at least one 1,1,1,5,5,5-hexafluoroacetylacetone as its ligand. In fact, it is preferable that each ligand of the metal complex is 1,1,1,5,5,5-hexafluoroacetylacetone.
Another ligand (other than 1,1,1,5,5,5-hexafluoroacetylacetone) of the metal complex (e.g., copper complex) can be selected from a hydrocarbon represented by the general formula (1), a cyclic hydrocarbon (optionally having a C5-C18 side chain containing at least two double bond) represented by the general formula (2), and an unsaturated compound represented by the general formula (3),
R1xe2x89xa1R2xe2x80x83xe2x80x83(1)
where R1 and R2 are hydrocarbon groups having a carbon atom number of 1-8 or silicon-containing organic groups having a carbon atom number of 1-8,
PR3(R4)(R5)xe2x80x83xe2x80x83(2)
where R3, R4 and R5 are hydrogen atoms or hydrocarbon groups having a carbon atom number of 1-6,
R6(R7)(R8)Sixe2x80x94(CH2)nxe2x80x94C(R9)xe2x95x90CR10(R11)xe2x80x83xe2x80x83(3)
where R6, R7, R8, R9, R10 and R11 are hydrogen atoms, hydrocarbon groups having a carbon atom number of 1-6, or silicon-containing organic groups having a carbon atom number of 1-8; and n is 1 or 2. Concrete examples of the another ligand are trimethylvinylsilane(trimethylsilylethylene), triethylvinylsilane, 2-butyne, 1,5-cyclooctadiene, and cyclopentadiene.
Concrete examples of the metal complex are copper (II) bis(1,1,1,5,5,5-hexafluoroacetonato) and copper (II) (1,1,1,5,5,5-hexafluoroacetylacetonato)-(trimethylsilylethylene). A more preferable example is copper (II) bis(1,1,1,5,5,5-hexafluoroacetonato).
In order to hydrolyze the metal complex in the process, it may contain impurities (e.g. a free 1,1,1,5,5,5-hexafluoroacetylacetone or a 1,1,1,5,5,5-hexafluoroacetylacetone hydrate).
The procedures of the hydrolysis can exemplarily be conducted as follows, and may be modified by a person skilled in the art. Such modification is also included in the invention. At first, a reaction vessel is charged with the metal complex (optionally containing impurities), followed by addition of water and then an acid to conduct the hydrolysis (acid hydrolysis). It suffices to add the water in an amount to make the reaction mixture in the form of an aqueous solution. Furthermore, it suffices to add the acid in a catalytic amount. After that, an extraction solvent is added to the reaction liquid, followed by separating the organic layer and then by removing the solvent from the organic layer, thereby obtaining 1,1,1,5,5,5-hexafluoroacetylacetone dihydrate in the form of solid. According to need, it is possible to increase the temperature of the reaction vessel during the reaction in order to accelerate the reaction.
The reaction vessel can be made of a material (i.e., glass or fluorine-containing resin) or lined with such material. The acid may be a mineral acid (e.g., sulfuric acid, hydrochloric acid and nitric acid). The reaction temperature of the hydrolysis may be about 0-110xc2x0 C., preferably about 20-90xc2x0 C. If it is lower than 0xc2x0 C., the reaction rate may be too low. If it is higher than 110xc2x0 C., the yield of 1,1,1,5,5,5-hexafluoroacetylacetone dihydrate may become too low.
After the hydrolysis, the resulting 1,1,1,5,5,5-hexafluoroacetylacetone hydrate can be extracted from a reaction mixture with an extraction solvent (e.g., ether solvents and halogen-containing solvents). This extraction solvent is, of course, in the form of liquid, when it is used. Its boiling point is not particularly limited, and is preferably about 100xc2x0 C. or lower. Concrete examples of the ether solvent are diethyl ether, diisopropyl ether, diisobutyl ether, dibutyl ether, t-butyl methyl ether, tetrahydrofuran, anisole, and dioxane. Concrete examples of the halogen-containing solvent are methylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,2-bis(trifluoromethyl)benzene, 1,3-bis(trifluoromethyl)benzene, 1,4-bis(trifluoromethyl)benzene, and 2,4-dichlorobenzotrifluoride. Of these, ether solvents are preferable, and t-butyl methyl ether is particularly preferable.
It is possible to dehydrate 1,1,1,5,5,5-hexafluoroacetylacetone dihydrate, which has been prepared in accordance with the invention, by a conventional method for dehydrating organic materials by contacting dehydrating agent, for example, concentrated sulfuric acid, phosphorus pentoxide, calcium sulfate and the like, thereby obtaining its anhydride. R. Belford, J. Inorganic and Nuclear Chemistry, 1956, Vol. 2, pp. 11-31 discloses such method in which a dispersion is prepared by shaking 1,1,1,5,5,5-hexafluoroacetylacetone dihydrate with approximately three times its volume of 98% sulfuric acid. After the dispersion has been allowed to stand overnight, dehydration of the product is repeated with a fresh batch of sulfuric acid. The resulting upper layer is siphoned off and distilled, thereby obtaining the anhydride (yield: 98%) as a distillate between 70.0-70.2xc2x0 C. J. Amer. Chem. Soc., 78, 2790 (1956) discloses another method in which anhydrous calcium sulfate is mixed with 1,1,1,5,5,5-hexafluoroacetylacetone dihydrate. Then, the resulting mixture is heated. The distillate is again treated with anhydrous calcium sulfate and distilled, thereby obtaining the anhydride of a boiling point of 68xc2x0 C. (736 mm.). There is known a still another method in which 1,1,1,5,5,5-hexafluoroacetylacetone dihydrate, together with phosphorus pentoxide, is heated in ether.